1. Field
Example embodiments relate to electrode structures, gallium nitride based semiconductor devices including the same, and methods of manufacturing the same.
2. Description of the Related Art
A gallium nitride (GaN) based semiconductor has excellent material properties (e.g., a large energy gap, high thermal and chemical stability, high electron saturation speed (˜3×107 cm/sec), etc.). In particular, an electronic device employing a GaN-based semiconductor has various favorable characteristics (e.g., a high breakdown electric field (˜3×106 V/cm), a high maximum current density, stable operation characteristics at high temperatures, high thermal conductivity, etc.). In the case of a heterostructure field effect transistor (HFET) using a GaN-based heterojunction structure, electrons may be densely concentrated at the junction interface because band-discontinuity at a junction interface is large. Thus, electron mobility may increase. Due to such a material property, a GaN-based semiconductor may be applied not only to an optical device but also to an electronic device configured for high frequency and/or high power, or to a power device.
However, when a GaN-based semiconductor is applied to various electronic devices (or, semiconductor devices), it may be important to develop an electrode having an excellent contact characteristic with respect to the GaN-based semiconductor. For example, development and/or improvement of an electrode capable of ohmically contacting the GaN-based semiconductor, and a method of manufacturing the electrode, may greatly enhance performance of an electronic device (or, a semiconductor device).